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How does an aircraft form wake turbulence?
This question discusses how wake turbulence can affect planes flying in formation.  It got me wondering, how do aircraft (the wings in particular) form wake turbulence to begin with?  It can't be as simple as tip vortexes right?
As a follow up, how can you design an aircraft to minimize wake turbulence?  And what are the trade offs in doing so?

any object that moves through a medium creates wake turbulence

FAA has a nice document about it.

@ratchetfreak: Is that really true? Can't the wake destruct itself? I mean if the object has the shape of a water drop, at subsonic speed, will it create a wake (no taking into account the volume very close to the object).

Origin of the vortices
Wake turbulence is easy to understand once you know how a wing creates lift: By deflecting the air flowing across it downwards. In this answer, I had used the simplification of just accelerating downwards all the air flowing through a circle with a diameter equal to the wingspan, and leaving all other air unaffected.
This helps to understand the principle of lift creation, but is too simple, of course, because the downward movement of air will create a void above it, and the air below has to make place for that downward moving streamtube. Also, the pressure field around the wing will affect the air in the vicinity of the streamtube as well, and in consequence air from below will be pushed sideways already by the wing, and the air above will start to flow towards the low pressure area over the wing. This sideways movement will become more pronounced aft of the wing, such that air will continuously be pressed outwards below the wing's wake, move up left and right of it and inwards above the wake. The inertia of the downwash keeps it moving downwards for several minutes, continuously displacing the air below it and sucking more air into the space above, and that will result in two vortices swirling behind the wing. This is the rolling up of the wake (see the sketch below, taken from this source).

The vortices are just a consequence of the downward movement of the wake, and this in turn is a consequence of lift creation. Please note that the cores of the vortices are closer together than the wingspan! This by itself should make clear that they are not caused by air flowing around wingtips, a hard to extinguish misconception. The table below gives calculations of this vortex spacing.

The table is also from the Carten paper of 1971; note the inclusion of Boeing's 2707 project!
Strength of the vortices
If we again come back to the simplified streamtube approximation, lift is proportional to the mass of air flowing through it per unit of time times the deflection angle. If lift is equal to the aircraft's mass (as it should be), heavy aircraft need to either accelerate more air (wider span) or accelerate air more (higher deflection angle) than light aircraft at the same speed. A higher deflection angle will produce more powerful vortices. For that reason, a heavy aircraft at low speed and with a small wingspan will produce the strongest vortices.
Since more air flows through the streamtube at higher flight speed, flying faster will require less deflection, making the wake vortices weaker. If the aircraft climbs, air becomes less dense with altitude, and less mass flow over the wing is available, so the vortices grow stronger if the flight speed does not change. Normally, aircraft accelerate when climbing, and the vortex strength will stay the same if the aircraft flies at constant dynamic pressure.
Vortices can be avoided in three ways:

Infinite wing span (meaning infinite mass flow, so no deflection is necessary for any lift)
Infinite speed (again, gives infinite mass flow)
No weight of the aircraft. Flying a zero-g parabola does indeed produce almost no wake turbulence.

End of the vortices
Inertia will keep the wake moving downwards and the vortices spinning, but friction will let those air movements die down within a few minutes. If the aircraft flies high, the wake is dissipated long before it hits the ground. The wake of low flying aircraft, however, does hit the ground and is deflected. The vortex tube now acts like a wheel and starts moving outward, and if there is a sufficient crosswind, the windward vortex can be arrested as in the right sketch below (also from the Carten report).

Photographic evidence
There are far too many pretty pictures around of wake vortices to not include some, so I will add a few here:

You can see that the outer contrails of this Boeing 747's engines wrap around the contrails of the inner engines. This shows how the air is pushed down in the wake of the wing and that the centers of the vortices are slightly inboard of the outer engines.

The condensation traces originating at the winglet tips of this A340 move in- and upward, again showing that the vortex does not originate from the tips but forms behind the wing and with a distance between the two vortex cores of substantially less than the wingspan.

These two pictures show how the downwash of the wake is cutting a furrow in the clouds.

KLM MD-11 on a moist day, flaps set for landing (source © Erwin van Dijck). One, it shows how insignificant the tip vortex is compared to vorticity shed at the flap tips, and Two it shows how the tip vortex moves inward and starts to be sucked into the wake vortex. Note also the tip vortices from the tail!

I like the NASA image, pretty colors and all that: http://commons.wikimedia.org/wiki/File:Airplane_vortex_edit.jpg

@Peter Kämpf, it seems some of your pictures got taken offline, would you mind finding similar ones that are still working? Thanks :)

@ROIMaison: They all load on my side. Please look up the imgur URL in the source and try to load them directly. Maybe a server was overloaded - they should all still be online.

@PeterKämpf, I tried exactly that, and it wasn't working. The images are working now, so I guess it was a temporary thing. Thanks!

@ROIMaison: I had this happen to me just now. On the second attempt (reloading the whole page) the missing imgur file loaded as well. I guess they need to work on their bandwidth.

So wing tip vortices are created because downwash curls back up to fill the void above it's self and this void is created because the air is going down which causes less air above

@Crafterguy: Please replace "wingtip" by "wake" and your sentence is much improved. Downwash moves down; what moves up left and right of it is actually an upwash, and yes, this curls up to fill the void above the downwash.

Why would the vortices not be caused by airflow around the wing tips? why would airflow around the wingtips not contribute to the wake?

@Crafterguy: I added another picture. Yes, airflow around the tips adds to the wake, but the amount is insignificant. The wake vortices are caused by vorticity shed over the wingspan.

@PeterKämpf - do the winglets on the MD-11 (and A340) have something to do with the behavior of the vortices shown in those images?  P.S. Thank you for the cool pics!

@pr1268: Well, they change the location where the wing ends. Not much else. Without winglets the vortex would be much the same, only a little more stronger.

@PeterKämpf what is the influence of flap deflection on the wake vortices?

It is as simple as "tip" vortices, but that is a misnomer.
The wing vortices are not really caused by the "tips". They are inherent effect of generating lift over finite wingspan. To generate lift (a force on the plane), the aircraft applies force on the surrounding air (by Newton's third law). Since the air is free to move, this force accelerates it (according to Newton's second law) downward. Due to the way fluids work the force affects air both above and below the wing (to height comparable to wingspan), but not to the sides.

So directly behind the plane we have air that is moving down and on the sides air that remains still. And this is the wing vortices. See also John S. Denker: How It Flies, section 3.14.
There is slight updraft just outside the wingtips caused by the transverse flow around the wing tip, but it only contributes a tiny fraction (at most couple of percent) of the circulation and associated drag. There is also some turbulence caused by simply moving through the air at sufficient speed, but that is comparably minor as well.
The inertia the aircraft has to impart to the air over unit of time is proportional to the aircraft weight. Therefore turbulence behind heavier aircraft is stronger.
If the aircraft flies faster it affects more air per unit of time, so it suffices to accelerate it to lower speed. Therefore turbulence behind slower flying aircraft (e.g. during take-off or landing) is stronger.
If the aircraft flies higher the air is less dense (has lower mass per unit of volume) so it needs to be accelerated to higher speed. Therefore turbulence behind aircraft flying higher is stronger. Fortunately when flying high aircraft also fly fast.

I liked that you addressed that turbulence is stronger behind slower aircraft, which is non-intuitive.

Could possibly expand the section on how a slow flying plane creates more wake turbulence that a fast flying one?  I feel like I'm poking the edges of understanding that but...  I could use some clarification.

Are wingtips at all relevant here? Do they affect the vortices significantly or no?

@raptortech97: Not significantly. There is a tiny bit of upward flow around the tip, but it is very small compared to the downwash behind the wing. The various winglet designs have more to do with lift distribution and bending moment than saving any induced drag and corresponding energy of the wake vortex. See this answer for detailed explanation of winglets.

There is nothing wrong in this answer, but the picture is misleading: There is a sheet of vortices leaving the wing, not just two isolated ones at the wingtips. Anyway, using the mechanics of the Biot-Savart law to explain lift makes the topic needlessly convoluted.

@JayCarr If an aircraft is going fast, it pushes a lot of air a little bit. If it's going slower, it pushes a little bit of air a lot.


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Does a plane have brakes to stop or slow down while flying?
Does a plane have brakes to stop or slow down while flying?
For example, if the pilots see a large flock of birds at some distance in front of the airplane, and they want to reduce speed suddenly. What will happen if an airplane doesn't have such brake?

"Can a plane *stop* while flying?"  Really??

Insofar as jetliners are concerned, birds, even flocks, typically can't  be seen at a far enough distance to allow significant slowing even with, say, reducing the thrust to idle and deploying drag devices.

vote to close?.

An airplane can slow down and reduce its speed while in flight. The easiest way to do so is to reduce the amount of thrust that the engines are producing. This will produce an almost immediate reduction of the airspeed, especially if the plane is maintaining the same altitude.
There are also devices called air brakes and spoilers that can be further used to reduce speed. These, however, are never1 used in normal, level flight by passenger2 aircraft and are normally only used to reduce speed during the descent and landing phases of the aircraft3.
If an airplane reduces its speed too much, it will of course stall and start dropping precipitously, at which time the airspeed usually also increases again. The slowest speed an aircraft can maintain at a given altitude without stalling is listed in its flight envelope.
However in the scenario you mentioned (obstacles ahead), it's usually easiest to simply fly around the obstacle.

1: Never say never on the internet.
2: The situation is different in military aircrafts, you can see the approaching Su-27 using its airbrake in this video
3: The wheels of most aircraft also have brakes, similar to those found on automobiles. Obviously these can only be used when the plane is touching the ground. Lowering retracted landing gear will also increase drag. There are also thrust reversers on some aircraft that are used in the final stages of landing. Use of thrust reversers during flight can be disastrous although some older aircraft (including the C-17A) were designed to use thrust reversal to scrub speed in-flight.
Finally, some gliders and larger aircraft have drag or drogue parachutes to help slow them down, for example for use on short runways.

@RoboKaren spoilers are used somewhat frequently in the air as well. They're used to quickly loss altitude during the descend phase of the flight. With efficient wings like B777 and A330, the aircraft is slippery. It can also be an indication that your flight is arriving early (-:

That would be "landing the aircraft" in my answer. :-)

I'd refer "landing" to the phase from Final Approach Fix to touchdown (with gear and flaps extended), and "descend" happens much higher and at a larger magnitude, e.g. FL400 to FL280 or 12,000 to 4,000.

@kevin: Spoilers are used somewhat frequently to hasten the descent, but pilots always try to avoid it, because it always means higher fuel burn (during the spoiler deployment engines are at idle, but it means either the power should have been reduced earlier or that more flying under power at low altitude remains).

@JanHudec true. The FMCs compute the most efficient descend profile, which usually a long portion is an engine idle descent. Ideally it starts at Top-Of-Descend, but we all know sometimes we just don't get what we want. Another reason not to use it, is spoilers introduces a bit of vibration to the airframe and thus a bit of uncomfortable for the passengers.

@RoboKaren if you simply reduce thrust you will also loose altitude. For what this question is asking, slower speed can be achieved by increasing back-pressure too, isn't that correct? I am no expert. I am just going by the theory I am learning and would appreciate anyone giving me positive feedback if there is a lack of understanding in my comment.

Video link on n°2 is broken

@Antzi - fixed the video

@yankeemike Yes, that's correct. Karen is right that you can reduce power and maintain altitude in the short term, in which case you'll lose speed (rather quickly, depending on how much you pulled back on the power.) However, you'll have to keep pulling back further and further to maintain altitude as you lose airspeed and eventually you'll stall. Indeed, this is exactly the procedure for practicing a stall. This is all assuming that you were previously flying at the most efficient airspeed/attitude for your altitude.

@yankeemike However, if you just reduce power without pulling back or adjusting the trim, you're correct that you'll start descending while maintain approximately the same airspeed. You trim for an airspeed, not a vertical speed.

You can also "crab", which is the extreme opposite of being in "trim". Essentially, you turn the ailerons opposite the rudder and keep the nose down so it doesn't stall. The plane ends up going thru the air diagonally, presenting one side of the body to the air. That produces a lot of drag. It is a great way to lose altitude quickly in a small plane. It's normally done at low speed, and feels strange to passengers. Best to go gently at higher speeds. Too much exuberance might stress a weak airframe.

I used to fly a Rallye Minerva which was already a pretty draggy STOL aircraft. When combined with crabbing, it could descend very quickly. One has to be careful as the configuration is just right for popping into a spin (not a real consideration in the Minerva).

No a plane doesn't stop in midair, planes need to keep moving forward to remain in the air (unless they are VTOL capable).
What it can do is simply turn around or go over/under the obstruction.
VTOL means vertical takeoff and landing. It essentially means they can hover in place like a helicopter.

Can a VTOL plane hover without ground effect as well?

@vasin1987 - Yes, a Harrier or Osprey, for example, can both hover a long way out of ground effect, although not as high as it can fly in "plane mode"

@JonStory: It depends on weight. AFAIK Harrier can be loaded to the point it can't hover at all and needs to take-off with short ground roll.

Well yes, but that's not an altitude limited thing: it either can or can't hover and, unlike a helicopter, ground effect makes no difference due to the fact it's not aerodynamic lift from a rotor, it's direct thrust from the jet engine.

What about the air brake?

@GabrielBrito Most airplanes have no such thing as an 'air brake.' Many larger aircraft have spoilers, but the primary purpose of these is to reduce lift, not so much to directly slow down the plane (though they do have some degree of that effect, also.) Slowing down is generally accomplished by reducing power and/or increasing pitch. Spoilers can be used in combination with increased pitch to slow down without climbing (particularly in the situation that the engine(s) are already at flight idle and can't be reduced further.)

Many jets & gliders have spoilers or airbrakes.
They  function by adding drag and, in some cases, reducing available lift.
When an aircraft descends, speed builds up unless the energy is dissipated in some way. Modern aircraft have fairly clean design which means it takes a while
to 'bleed' off the energy. This is good for energy efficiency, but is problematic when you need to descend quickly, for example during an approach or flying around significant thermals.
Propellers often provide a natural speed brake when power is removed and so act as an airbrake, but jets & gliders do not have this option.
As mentioned in other answers, there is a minimum speed below which the aircraft cannot fly, however avoidance of issues such as birds, smoke, etc., is usually performed by change of direction or altitude rather than slowing down.

Dive bombers like the SBD Dauntless or the Ju 87 also had dive brakes, for the same reasons you mentioned -- to keep below Vne while diving on a target.

Especially with gliders, the glide ratio is so high that you pretty much need spoiler/air brakes to maintain a reasonable descent profile when landing.

There are many planes fitted with air brakes. StuKas, for example:

To prevent the airplane from building up too much speed, dive brakes (large perforated flaps) are needed.

Similarly, flaps are/were used to "brake" when landing.
But: They won't be used to slow down because of "flying cows" "grazing" on the "air street", like cars would. Either a plane can turn to evade the birds, or it will have to go right through them. But then, if you can believe one Cpt. Sullenberger, you won't even see a bird strike coming like that...

Airplanes can slow down in a variety of ways.  The most common is actually to pull the nose up and start climbing - it trades the energy of velocity for height and avoides the object in front of you.  Think of what happens when you are riding a bicycle up a hill and stop pedalling.
Reducing the throttle allows the friction of the air the plane is moving through to slow the airplane as well.  Think of putting a car in neutral while driving on level ground.  If the pilot doesn't also raise the nose of the plane as it slows down, the loss of airspeed over the wings will result in a reduction of lift and the plane will start descending and the reduced altitude will help avoid an airborn object.
The use of flaps will increase both drag and lift of the wings.  It will slow the airplane and cause a change in altitude which the pilot can manage by slightly lowering the nose as the flaps go down.  However, flaps have a maximum extension speed (often well below cruise speeds) so they aren't practical for obstacle avoidance.
Spoilers disrupt the airflow over the top of the wings to reduce lift.  They have a side effect of increasing drag but it's less of an impact than the loss of lift.  The primary purpose of spoilers is to increase the approach angle to the runway without changing airspeed or attitude.
With this many options, the real answer to obstacle avoidance isn't slowing down: it's steering around.  Going left, right, up or down to avoid the obstacle is much more effective and is what all pilots are taught and what all automated collision avoidance systems use.

In high performance tactical jets there are 3 ways to reduce airspeed that are quite commonly used. For example, in the US Navy the landing pattern is entered at 250 knots, 800 feet AGL and then a turn made to downwind, with a descent to 600 feet, while slowing to landing speed. For the A7E pattern speed was, depending on fuel weight, around 125 knots. To bleed off all that energy we used the "break," which is a high-g level turn. Of course 250 knots is SOP, but at times, one might come into the pattern at over 600 knots, in which case the break was an absolute necessity to get the aircraft to 125 knots.
The other common way to slow down while in flight was to point the nose up, trading energy for altitude. But perhaps the most efficient way of reducing speed was using the speed break. On the A7 this was a "barn door" that was extended below the aircraft with a button by the pilot. It was very good at bleeding off energy at high speeds. In fact, it was part of the "break" maneuver described above. When not needed it withdrew into the aircraft, and left a flush aerodynamic fuselage. Another use was during a dog fight, hopefully catching your opponent who was at your 6 o'clock off guard, and causing them to overshoot you. This was always a rather desperate move.
On one occasion, I approached the flight lead to join formation at a closure rate of around 200 knots. He was at 250 and I was at 450 as I rocketed towards him. I was close and extended the speed brake, while looking at my airspeed indicator needle drop. Well it wasn't quite dropping, more like kinda moving towards 250. I retracted the speed brake, and felt the aircraft stop decelerating, as I approached fast down his right wing line. At around 10 aircraft lengths away I pulled hard up, and slammed the stick over to the left, never letting up on the back stick. I emerged on his right wing in perfect formation.
By the way this maneuver, or something like it is also used in dog fighting to keep from overshooting an opponent.

Hi Aaron, a very nice story about your experience and I enjoyed reading it. Unfortunately, the story-telling approach does not fit Stack Exchange very well, which is a Q&A site and answers should be "to the point". Hence, I removed a substantial amount in your answer. For anyone passing by, feel free to go to the edit history and read the entire story, because it surely is nice!

No problems, figured as such.

There are 4 forces that act on a plane: thrust, drag, lift, and weight.
Planes slow down because of drag.  Once power is reduced, drag is greater than thrust and causes the plane to slow down.
UPDATE
Sorry, I'm pretty new here and probably didn't include enough information in my original answer so here's a more thorough answer from the FAA Pilot's Handbook of Aeronautical Knowledge:

In steady flight, the sum of these opposing forces is always zero.
  There can be no unbalanced forces in steady, straight flight based
  upon Newton’s Third Law, which states that for every action or force
  there is an equal, but opposite, reaction or force. This is true
  whether flying level or when climbing or descending. It does not mean
  the four forces are equal. It means the opposing forces are equal to,
  and thereby cancel, the effects of each other.
[...]
For an aircraft to move, thrust must be exerted and be greater than
  drag. The aircraft will continue to move and gain speed until thrust
  and drag are equal. In order to maintain a constant airspeed, thrust
  and drag must remain equal, just as lift and weight must be equal to
  maintain a constant altitude. If in level flight, the engine power is
  reduced, the thrust is lessened, and the aircraft slows down. As long
  as the thrust is less than the drag, the aircraft continues to
  decelerate until its airspeed is insufficient to support it in the
  air. Likewise, if the engine power is increased, thrust becomes
  greater than drag and the airspeed increases. As long as the thrust
  continues to be greater than the drag, the aircraft continues to
  accelerate. When drag equals thrust, the aircraft flies at a constant
  airspeed.

I don't think you really meant to say that. Mathematically, drag can never exceed thrust: when drag and thrust are equalised, the aircraft must stall; so a situation can never arise in which drag can be greater than thrust.

@Ed999 - when thrust equals drag then Newton reckons it'll continue at the same speed because the forces are balanced and I'm not going to argue with him.

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Are 'human factor' specialists consulted during the UX design of cockpit controls and avionics?
I have always been struck by the complexity of cockpit controls. Aviation specialists are always on the hunt for ways to reduce cognitive overload on pilots to reduce human error.
That being said, air crash investigations have proven in a number of incidents that labelling, controls interactivity, affordances and other interface design issues impact on how pilots operate.
So, I have few questions:

How do human factor specialists and user experience designers differ (or not) when it comes to designing for avionics?
If user experience design skills are so different from human factor skills, wouldn't they be required when designing avionics?
If they are not so different has anyone came across a situation where user experience skills were utilised within the aviation industry?

related: Why are the cockpit controls of airplanes so complicated? Most important thing to take away there is that there are conventions already in place and rule number 1 of UX is to change as little as possible with the new iteration.

User interface design is too young to have had a meaningful contribution, and in reality workload is so light in normal operation that pilots will likely be 'out of the loop' when something goes wrong. The trend is to reduce automation again.

I am not very familiar with the User Experience field, to me it seems it is a subdomain of Human Factors and kind of a buzzword lately. I can't answer your questions 1) and 2). If 3) is looking for design choice in (visual) interfaces that reduce probability of misinterpretations there are lots of examples.

Human factors and user experience are intertwined. I don't think you can really pitch one up against the other.

@PeterKämpf I disagree with a few things in your comment.
User interface design has been studied for a while. See http://www4.lu.se/upload/Trafikflyghogskolan/TR2003-02_HumanFactorsinAviationaNaturalHistory.pdf
"Normal operations" include selecting the correct flight plan in the autopilot.
Also, the phrase "user interface" does not exclusively refer to computer interfaces, so automation is not key.
In short, user interface design can very well have had a meaningful contribution.

@usernumber: Now we get down to details of definition. UX design is too new, but the work by Frederick Taylor or Frank and Lilian Gilbreth found plenty use in aircraft design, but not universally so. German pilots were both amused and appalled at the haphazard and illogical cockpit layout of British aircraft, being used to a well thought-out standard which was followed in Germany. But it was not called UX design.

It would be nice if the body of the question explained what "UX" means.

My thesis, which I wrote so long ago that I no longer recall the title, was a complete redesign of the Boeing 747 cockpit from a human factors and usability point of view.
My designs, which were submitted to Boeing at the time, likely helped create the foundation for the modern glass fly-by-wire cockpit.
At the time, glass cockpits did not exist (the term refers to the glass in the CRT monitors that were eventually used within the cockpit, later replaced by LCD displays).  Fly-by-wire, which is the concept of replacing conventional flight controls with an electronic interface, was in its infancy.
I remember working tirelessly to create a comprehensive new human interface for pilots that would minimize errors and improve safety.
My research was based in the cognitive sciences, which consisted of university coursework in human physiology, neuroanatomy (rudimentary at the time), psychology, statistics, engineering, computer science, mathematics, linguistics, neural networks (the very first ones), and artificial intelligence.  It was a rigorous and diverse education.
I spent hours and hours watching films of pilots performing a vast array of different procedures.  Sometimes they were successful, and sometimes they were not.  When they were not, it often resulted in serious consequences.  I spent long nights listening to hour after hour of dialog between air traffic controllers and pilots.  I studied detailed accident and near-accident reports.  I also interviewed pilots and spent a fair amount of time inside commercial cockpits, between flights, gathering essential data.
One of the challenges that I vividly recall was reducing complexity for pilots, while keeping the tasks difficult enough so they would stay engaged to their tasks and not fall asleep or become distracted.
The most rewarding part of developing my thesis was converting the cockpit from what I called a control-based center to a task-based center.  Up until that time, most controls available to pilots were designed to directly impact a flight control surface such as the rudder.  There were some rudimentary "intelligent" controls to perform basic horizontal and vertical navigation (but nothing that integrated the two!).
I designed a new system that was based on high level tasks that the pilot would need to perform.  No longer were ailerons, elevators, flaps, and thrust the focus.  Instead, I changed the focus of the cockpit to center on essential tasks such as taking off, landing, route planning, communications, and traffic and weather avoidance.
During this work, I learned that I had to seamlessly integrate my human factors engineering and user experience design skills.  In my opinion, and from my personal experience, they always need to be.
Whenever I fly, I ask to take a look at the cockpit after we land.  It's a joy to see the evolution of my designs.  Whether I was the originator of these designs or one of many human factors engineers who came up with them at the same time, I will never know.  But similarities of the current designs to what I proposed in my thesis many years ago gives me a little insight into a possible answer to that question.

Was that through UW's HCDE program? I know they work with the Boeing Flight Deck Concept Center.

Hey I am researching on this topic for a series about UX in critical areas. Would you open for a quick? jon@uitogether (dotcom) (broken up to avoid spam)

@jonshariat Hi Jon. It looks like your sentence got truncated or mangled.  What I see is "Would you open for a quick?", which, well, is probably not what you meant to write!

Human factors, (cognitive) ergonomics or human-computer interaction have long been a concern in aviation. There are several different approaches (and, in particular, a few distinct national traditions) but, no matter how you want to call that field, there is a lot of attention, resources and research devoted to the interaction between human operators and their flying machines.
“User experience” or “UX design” has now become a rather broad catch-phrase but originally it was mostly meant in opposition to usability engineering and its narrow focus on effectiveness and efficiency. User experience is broader in that it devotes more attention to subjective enjoyment and other intangible factors and also on design (as opposed to assessment and incremental changes), all very interesting aspects of HCI but possibly less relevant to aviation.
Usability engineering in turn developed out of human factors (and to some extent in opposition to it as well), quickly focusing on lightweight approaches (“discount usability”), precisely because it was difficult to get as many resources for these concerns outside of traditional industrial domains like power plant control rooms and, yes, aviation (thus closing the loop).
Depending on how you choose to look at it, “user experience” has therefore played a role in human factors all along or is a new(ish) field that grew out of traditional human factors.
Beside the naming issues and history, there are a few major differences between, say, your average website and a cockpit (e.g. users' expertise level, regulatory constraints and company culture) so even if UX design, usability engineering, human factors and cognitive ergonomics are arguably conceptually related, it might be difficult to switch careers or make meaningful contributions to the other field(s) if you have a background in one of them.

1- My understanding is that the terms are related, but have different appliations. User experience is more about how the interface is perceived, and whether the users find it easy to learn/use. This has come into focus as computers become more and more a part of our daily lives. Human factors for aviation focuses more on the fact that there is a direct relationship between the user experience of the pilots and safety of flight. Human factors also looks into how easy it is to make mistakes, and how easy it is to see and process the required information.
2- Knowledge of user experience certainly would be useful in avionics, since the end goal is to provide control and information to the crew.
3- I'm not sure how closely it relates to user experience, but while NASA was running tests with their 737, they tested various ideas for the avionics. Chapter 3 discusses different methods of controlling the airplane as well as HUD and electronic display technology. Chapter 7 discusses the use of a touch interface for a datalink to ATC. It is interesting to note that even when some technologies were rated very highly by the crews in the program, various obstacles kept some of them from being applied further.

I suspect cockpits for complex aircraft like airliners are improving with regards to human factors due to glass cockpits which help to group information most important to the pilot in one place.
Just compare pictures of the 707 and 787 cockpits. Glass avionics make a huge difference.
With regards to specific avionics companies, I imagine they do have consultants when designing the interface. When it comes to avionics, I'm quie a fan of Garmin. All their devices from avionics to bike GPSs are well designed and intuitive to use. And given how Garmin releases products besides avionics to the general public, I'm sure they know thing of two about good interface design.

This answer seems to consist entirely of supposition. We're looking for something more fact-based and verifiable, wherever possible.

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How can I get more details about information in a NOTAM?
In doing some planning for an upcoming flight, I noticed my destination (a towered airport) has a NOTAM about the runway: "FICON PATCHY ICE". That seems rather vague, I'd like more information before departing. Who should I contact to get more details about the runway conditions and how it might affect my flight?

What, you dislike the fact that the NOTAM about patchy ice is patchy in its detail? :)
Generally if you need more information about a NOTAM (in the US) you can check with:

Flight Service
While collecting your briefing ask if they have any more detail -- sometimes they do, sometimes they don't, but it's worth asking.
A local FBO
Particularly for FICON NOTAMs - A local FBO will usually know the condition of the field, and often have other useful info for you (like how much a heated hangar is going to cost you for the night).
Airport Operations
Again, particularly for FICON NOTAMs - These guys will usually have a pretty good picture of the field's condition, since they're generally the poor shmucks responsible for doing the snow/ice clearing.

Failing all of those, you can also call the tower phone number at a towered field (you can get that number from Flight Service too) and ask them for details.
I usually make the tower my last resort call - they're almost certainly going to be willing to give you as much information as they can, but they're also busy doing other stuff like dealing with planes taking off/landing/taxiing around & they'd probably appreciate if we tried the other sources first.
The other folks I mentioned generally have someone sitting around to answer phones and questions.
In the case of Flight Service, that's basically their job :-)

I would make calling the tower your last resort—we just get the NOTAM off the printer once the airport authority submits it, we don't really know much more about it than what's printed there. Airport ops should be your first option, because they were the ones who drove out there and reported the conditions.

Well this NOTAM really doesn't give a good impression of what's the actual condition is, but I appreciate you being keen to get some detailed information prior getting there. You should consider to call the airport manager - find the number e.g. at skyvector, but I wouldn't wait until the date of your departure, as these people are sometimes not easy to contact and it needs several tries, but of cause the information, especially regarding this NOTAM,  should be as up to date as possible. A local FBO could also provide you with some more detailed information.

This really is a pretty awful FICON NOTAM as far as level of detail goes. I'm used to seeing "ALL RWYS LOOSE DRY SNOW" or "PATCHY ICE TWYS A,B,G,D" or my personal favorite "4FT SNOW BANKS ADJACENT TO ALL MOVEMENT AREAS"  -- something that gives you a clue about the actual conditions.

In such a case the best action would be to call the tower's published telephone number. They will have more information regarding this notam (and might even have created it themselves) .

Your suggestion is not a good one because both your assertions are false. ATC doesn't issue FICON NOTAMs, the airport authority does. If you happen to know the tower's number but not Ops', you could call and ask them for it, I guess.


text:
How much does it cost to learn to fly in the UK, and what restrictions are there?
Flying has been a dream for me since I was a little boy. My absolute dream career was to be a fighter pilot in the RAF. It's obviously a very hard career to get into, however I fell even before the first hurdle when I found out that I'm colour blind.
Finding out I was colour blind actually closed a lot of potentially enjoyable careers. Police, Armed Forces, Electrical all reject colour blind people.
I'd love to be able to fly, freely in a light aircraft - something like a glider or mosquito helicopter, but I just can't figure out where I need to start. Also, I'm not sure if it's financially viable.
Could someone give me a breakdown of costs and commitments needed?
Also, I'm assuming that being colour blind doesn't automatically mean I'm not able to fly?
Also, I'm in the UK

It's not a dupe because it's a different country...

Note that commercial pilot career may not be closed to you. There is a retired 747 captain around who apparently is colour-blind. The light signals are probably the only situation where you need to recognize some colours and it's only three of them.

As others have already mentioned, it is definitely possible to do a private pilot license while being color blind. A friend of mine did that and even got the necessary qualifications for landings on a glacier.

My recommendation is: Join a glider club. This limits the expense and puts you into contact with many like-minded people. Make sure the club has several gliding instructors, so you will have enough chance for training lessons.
Did you try the UK gliding club finder yet?
I prefer gliders over powered aircraft because they expose you to the weather and the laws of aerodynamics much more directly. Also, the expenses per hour are much lower. At most clubs, you can expect to pay around £20 per hour to hire a glider, around £30 for an aerotow launch and around £8 for a winch launch.

There are a number of ways to 'get in the air'. Peter's mention of gliding is a good one. The requirements to get a glider license are substantially lower than any of the routes to a powered license. However it has obvious restrictions on weather, distance passengers etc. Time spent flying a glider will not count towards your requirements for a powered license if you decide to get one (though obviously many of the skills are transferrable). Gliding is also cheaper than other forms of aviation.
The next easiest way to get into the air is through a microlight permit. That's slightly more regulated than a glider, with slightly higher requirements, but also has restrictions on speed, passengers distance, weather, comfort etc.
The route with the highest requirements to get qualified, and also the highest cost, is the private pilots license. However that will get you the ability to fly an aircraft with a much higher comfort, capability and performance level. It's also opens up the route to more certifications - twin engines, instrument flying, commercial flying and even airlines (technically you can be a commercial glider or microlight pilot, but it's much rarer).
Only you can decide which route you prefer, taking into account all the factors.
The best way to find out about how you could achieve each one is to visit a club or a school where they do each. There are flying clubs or schools at virtually every working airport, and the internet will give you a list of glider or microlight clubs.

and check the medical requirements before you even begin. In my case that saved me a lot of money as I found out I'd almost certainly fail the medical after a year or two of training and flying (my eyes at the time were rapidly degrading, the expectation being I'd be what turned out to be below minimum within a few years. Luckily that's slowed down now and I'd be marginal).

From my reading of this (https://www.caa.co.uk/default.aspx?catid=49&pagetype=90&pageid=13879), colour-blindness means you can't get a class 1 (commercial) medical, but can get a class 2 (private) with a restriction that bars you from night flying.
I'm neither a medic nor colour-blind though so I'd definitely recommend you get in touch with an AME (authorised medical examiner, who you'll need to see anyway before going solo) to check before you pay for much training!
Costs for a full PPL... depends a lot on area, school, airport etc but you might be looking at something approaching £10k. That's £150/hr for a cheap plane, £30/hr for an instructor, and let's call it 50 hours (45 minimum + the exam + some leeway) to get 9k. Then 9 ground exams @ £25 = 225, and new study guides which are about £120 (I got mine 2nd hand from eBay for about £40 but the syllabus has changed; I've no idea how much). Initial medical exam is around £200, skills test around £170, CAA admin another £180. Oh, and your flying school may want a membership fee, let's say £100/year. That's, what, £9975? I've taken a few shortcuts (e.g. maybe you won't need 50hrs and I've ignored cheap stuff like a logbook, kneeboard, ruler marked in nm) but £10k seems reasonable to me as a rough estimate.
I've also ignored landing fees. My local fees were included but you'll need a few land-aways (at least 4?) at £10-20 each. Beware of the "local fees" thing... I've spoken to people who found much cheaper lessons elsewhere, but they didn't include any landing fees. I reckon I booked at least 100 landings/touch&gos during my PPL, which would have made that "cheap" rate a lot less appealing.

From the CAA website, MED.B.075 Colour vision:
(a) Applicants shall be assessed as unfit, where they cannot demonstrate their ability to readily perceive the colour that are necessary for the safe exercise of the privileges of the licence.
(b) Examination and assessment
(1) Applicants shall be subjected to the Ishihara test for the initial issue of a medical certificate. Applicants who pass that test may be assessed as fit.
(2) For a class 1 medical certificate:
(i) Applicants who do not pass the Ishihara test shall be referred to the medical assessor of the licensing authority and shall undergo further colour perception testing to establish whether they are colour safe.
(ii) Applicants shall be normal trichromats or shall be colour safe.
(iii) Applicants who fail further colour perception testing shall be assessed as unfit.
(3) For a class 2 medical certificate:
(i) Applicants who do not pass the Ishihara test shall undergo further colour perception testing to establish whether they are colour safe.
(ii) Applicants who do not have satisfactory perception of colours shall be limited to exercising the privileges of the applicable licence in daytime only.


text:
Do companies based in non-English-speaking countries require intra-cockpit procedural communication to be performed in English?
I was watching a video of an MD-11 landing in Quito, Ecuador
The crew is German (Lufthansa).
When they speak with ATC it's in English (obviously).
When they speak with each other it's in German (also obvious).
But, when they go through flight procedures, they speak in English.
Why do they not speak in German?
Is this required for the Cockpit Voice Recorder?
In this exchange the pilot is talking through part of the approach with her copilot, who then says

Genau

which means "I agree" in German, then immediately afterwards he says

Gear down

notice how both sound very similar.  Further in the flight the copilot, calls

Flaps 50

why not

Flaps fünfzig

This is common in many international airlines.
Lufthansa Standard Operating Procedure (SOP) dictates that all flight procedural communication (checklists, standard callouts, etc.) are done in English.
The only "German" I've seen on Lufthansa's checklists is "handy .... off" in the pre-startup checklist (German English for "mobile phone .... off").

ymb1's comment provides a good reason for this SOP but it would also be good to address that here.

From Air India B777 SOP: "Use standard phraseology at all times.
All procedural communication within and from the cockpit will be
in a common language ‘English’."

I suspect that the checklists etc. are still written in English, and not having to mentally translate from the English checklist to the German statement to the English checklist, even for someone who is fluent in both languages, may save precious moments even at times of low stress, let alone in a high-stress situation. Consistency!

@Mins India is potentially a special case, however - English is the common tongue in India, in many business circumstances

authors: Алексей Зотов


text:
How do pilots stay disciplined and use checklists, even after they have become routine?
I originally asked the same question on Space Exploration but will repeat it also here:
Before every takeoff and every landing, there are several routine checks which need to be done in order to provide the highest maximum safety to passengers.
But after certain number of repetitions, these tasks can feel as tedious especially if you are flying a plane which goes in "turns"
(Real example of what I mean is commercial line between Prague (PRG) and Frankfurt (FRA) where plane lands, people go out, new people go in and plane goes back. And so on)
How do pilots and other personnel make sure that they actually do go through the check every single time without "It was OK last time, so it will be ok this time. Skip it and say it is ok" ?

Because if they skip it and it was not ok they can be fired and lose their license

Because if they skip it and it was not ok they could DIE.

Yup, as both before me pointed out, it's not even like the can opt out of the checklists. The cockpit consists of two people, one reading/actioning the checklist, the other one monitoring and checking/cross-checking. If you say: "Nah, no checklist today", your copilot is bound to say: "Sorry, but we have to!" Your own life depends on it as well...

Interestingly enough, in other fields, seeing the success they have in aviation, people are trying to introduce checklists as a way to combat errors grounded in routine. See http://www.newyorker.com/magazine/2007/12/10/the-checklist and http://wikipedia.org/wiki/The_Checklist_Manifesto

Do they really really not skip checklists, though? Because apparently commercial airline pilots also sleep in flight even when they're not supposed to (e.g. captain at the same time as the first officer), so I'm wondering if the facts are actually lining up with reality.

@Mehrdad In four years in an airline cockpit I only encountered 1 person who didn't respect checklists. Perhaps not coincidentally he did not make it through his probationary year and was fired.

Just because some people break the rules, it doesn't mean that the rule is not nearly universally followed.

@Mehrdad The sleeping thing is very uncommon, especially for both pilots. In the U.S., neither of the pilots on the flight deck are allowed to sleep, which decreases the chance of both of them accidentally falling asleep to near zero.

@reirab: I was reading this (WARNING before you click: there's too much information in there that you probably don't want to know, so think twice before clicking), and it said "PILOTS ARE SLEEPING MOST OF THE TIME. 1/2 of pilots sleep while flying and 1/3 of the time they wake up to find their partner asleep."

@Mehrdad I've read that before. There are a few true things in there, but much of it is pure nonsense. The part about pilots sleeping is part of the nonsense.

@reirab: Ahh, I searched some more and apparently it's true, but it's not about the US!

@Mehrdad It's legal for one pilot to sleep in Europe, not so in the U.S. However, 40% of pilots admitting to it having happened is quite different from it happening 40% of the time. The former could simply mean that it's happened once or twice in their entire career.

@reirab: Great point!

Note that check lists' primary goal is to check you didn't forgot anything (although you may view it as a list of actions to perform).

@reirab "there are lies, damn lies and statistics" - Mark Twain. Your point is very valid.

You stay vigilant by having seen things go wrong.
Like Jamiec mentioned the importance of a proper preflight is drilled into you by your primary instructor from day one in light aircraft, and that mentality carries through all the way up to heavy transport-category aircraft: You want to find any problems you can while you're on the ground, because if you take a problem into the air with you it's a decision you can quickly come to regret.
Personally I've found all sorts of "interesting" things on preflight inspections of light aircraft, including (but not limited to):

Mud wasps building a nest in the pitot tube
Mud wasps building a nest in the fuel drain
(still don't know what was up with that)
Missing screws from a fairing
Flat-spot on a tire
A tennis ball stuffed in between two cylinders
(a common flight instructor trick to see if students are doing a thorough preflight)
Position light lenses installed backwards
(another common CFI trick, but this one was actually a maintenance shop screw-up)
Various light bulbs burned out
Water in the fuel after a heavy storm.

I've also heard some scary stories:

Migrating colony of bees hanging out on the tail of the aircraft
(described as "The tail was literally dripping bees")
Flight controls rigged backwards
Big gouge in the wingtip
(acquired by the previous pilot scraping the tip against another plane's tail taxiing in on the ramp)
The ever-classic "ran out of fuel because you didn't visually check the tanks"

I had a bird living in my horizontal stabilizer. We spotted straw during the preflight poking out of a lightening hole that gets exposed while the flight controls are locked (elevator deflects upward). Taped that over and we've been good ever since, but a hell of a shock.

@egid Ooh I forgot about birds nests! Our local birds prefer to nest in the engine cowling (because I bought a tailcone cover to keep them out of THERE) -- only sign of the nest on preflight was one stray piece of straw sticking out of one of the cowl vents, but it was right up between the front cylinders and the exhaust stack/mufflers when I pulled the cowling apart - prime fire-starting position. ("Split the cowl and look for nests" is now standard on my spring preflights. Stupid pyromaniac birds!)

Don't forget ran out of fuel because you were distracted by visually checking the tanks, and you don't know how the metric system works

My most memorable personal experience was the pair of pliers inside the engine fairing on a single engine piston light aircraft, right by the spark plugs. Now, that's a good reason to remember to do all the preflight checks...

A "crossed controls" incident occurred when I was in the US Air Force. The pilot pressed the rudder pedals before starting his engines and asked a ground crew if the tail moved. "Yup". Fortunately, the pilot figured out his rudder was reversed before he left the ground. In this case, the pilot was trying to run his checklist from memory.

At least you FOUND the wasps nesting in the pitot tube.

I'm surprised that nobody has mentioned the cat in the ultralight incident.

In commercial operations the vigilance to avoid complacency is derived from multiple reinforcing actions.
Checklists are often preceded by flows in which you take a logical route through the aircraft panels and perform your checks from memory.  These flows are then backed up by the checklist.  Checklists vary in usage. One one end of the spectrum you have silent checks performed by one pilot (e.g. the after takeoff checklist may be a silent checklist) and on the other end you have challenge and response checklists where one pilot reads each item and the pilot who accomplished that action reads the status of that system (e.g. you look at the button/light/etc and call its status rather than calling the response from rote memorization).
In an airline cockpit you might fly with the same pilot all month or you may change pilots every trip or sometimes multiple times during a trip.  Flying with many different people helps you standardize on these actions as you cannot "get comfortable" with a specific person.  Everyone expects everyone else to do the checklists properly and if you don't do it you will get called out.  Particularly as a new first officer if you are not doing checklists you are going end up explaining why to the chief pilot and/or training department.
You might then ask why we care so much about policing eachother to maintain checklist usage.  The FAA (in the USA) has made a big deal about checklist usage on every checkride you've taken to get into an airline cockpit (at least if you've done your training in the last decade).  It has been drilled into you from the beginning of your training.  In an airlne environment you will have recurrent checkrides every 6-12 months and captains will have line checks every year and proper checklist usage is among the most basic requirement to pass these checks.
Lastly, every year we sit through a day of crew resource management training and part of that day involves looking at past accidents and understanding what the first thing was that set the accident events in motion (pilot error!).  These often serve as vivid examples of how bad things can get if you start ignoring the checklists (among other things).

Awesome, detailed answer.  Also appreciate the comment on flows -- especially useful for emergency procedures, where a certain number of checklist items are expected to be memorized for immediate corrective action (and then verified by checklist, if time/conditions allow).

I can't speak for commercial operations, but from a GA point of view, the pre-flight checks and their importance are drilled in to you from your very first lesson. Its is stressed that the Pilot in Command is 100% responsible for verifying that the aircraft is fit for flight before even climbing in to the cabin.
There are a few tricks that are used to stop you falling in to that "Yeah, everything will be fine" mindset and just skipping the checks

Not doing the checks from memory, but actually doing them in reference to a physical check list.
A prescribed order of checks, starting at a point on the aircraft and moving around methodically
The fear of missing something, such as engine oil levels, which gets very serious once airborne.
Once carrying passengers, especially nervous ones, they tend to feel safer when they've seen you PHYSICALLY checking the aircraft before flying it.

"Not doing the checks from memory, but actually doing them in reference to a physical check list." There is a little controversy about this, because 50% of PPL/CPL holders I asked state they do it differently. They do the items from memory and thereafter verify them with the physical checklist. Must be something that depends on where you learned to fly, because I know it the way you described it, too...

GA pilots may be more lax, and there are certainly historical cases of missed checks causing accidents (and presumably, therefore, missed checks that they got away with)... Commercial pilots are highly unlikely to get away with it, but it does depend to some extent on the checklist. "Kick all 3 tires" can be verified after the fact on the checklist from memory, whereas a 787 pre-flight cannot.

@JonStory my understanding is that airline crews are taught to use checklists as proper check lists (complete a flow, run the checklist to verify (check) that all required items were in fact completed). For something complicated like a preflight that might mean stopping to review several sections of a checklist (Wing, Tail, Nose, etc. for the external check). The other way of using checklists is to treat them as "Do-List" (point at an item, do it, point at the next item, do that one, etc.) & there's lots of Human Factors research telling us that's not an ideal way to do things.

In short, discipline.
In my case, I learned the discipline to use a checklist for every action on every flight the one time I decided not to use a checklist while taxiing from the fuel pump back to the parking ramp. It was winter, and a snowplow pulled up behind me, so I decided not to use the checklist in the interest of expediency (ha!). I primed the engine, checked the fuel valve, engaged the electrical system, keyed the starter, and the engine responded by firing up and then immediately dieing. Repeat about a half-dozen times, at which point, I finally decided to use the checklist because something obviously wasn't right. Once again, primed the engine, checked the fuel valve, move the mixture to the rich posi--
Oh...I had left the mixture in the idle-cut-off position. Oops.
I've used a checklist religiously ever since then ;)

Well, I'm happy to see that I'm not the only one this happened too... Once flying the Beech Baron of my boss I also thought I know it all by heart... My boss (and also flying teacher at the time) was sitting beside me, smiling and just letting me desperatly try for like 10mins.

If you do it often enough, it becomes a habit. It then feels wrong to not run the checklist.
The only problem with all that repetition is that while you ran through all the items, you didn't actually do the thing which needed to be done on that occasion.
Case in point: Air Florida Flight 90. One of the checklist items was engine anti-ice. The crew of the accident flight was accustomed to flying in warm weather conditions. In such conditions, engine anti-ice is not necessary or appropriate, so the checklist action/response would always be "off". For the flight in question, engine anti-ice would have been at least a wise precaution if not critical to a safe takeoff, yet the habit prevailed and the takeoff was attempted without engine anti-ice. Without anti-ice, sensors were likely blocked with ice, causing incorrect readings on gauges indicating engine performance. This led the crew to apply insufficient power to accomplish the takeoff.

Aggravated by the aircraft needing more power to take off than it normally would, due to the wings also being contaminated with snow and ice.

For me, it's simply common sense. It's like with driving a car: I have been driving  for 13 years now and still drive as carefully as I did when I started. I have had one accident in that time; the other car and I skidded on a smooth road. But, we were both driving carefully (roughly 30kmh/20mph in a 80kmh/50mph zone) so nothing more than car body damage happened.
You cannot always prevent accidents by being careful but you can always attenuate the consequences.
I don't want to die nor do I want my guests to die from my negligence, so I am not negligent, be it with the car, the plane (for which I have not long had my licence) or even simply with the windows of my apartment on the 4th floor; negligence kills.

You seem to be confusing driving slowly with driving carefully. They're completely orthogonal. It's possible to drive carefully at 70mph and to drive carelessly at 7mph ("Look, ma!  No hands!"). I'm glad your crash wasn't serious but, arguably, the fact that you crashed at all (and that it wasn't entirely the other driver's fault) indicates that you weren't taking enough care.

The only way to make sure you don't have an accident is to never drive a car. Even the law says so: You're always responsible and to a certain extent accountable for just driving the car. No matter who did what in an accident: You always pay at least 25% of the damage simply because it's your fault to have taken the car.

I have a checklist for stopping at stop signs. People often think they come to a full stop, but from the outside, if you watch their wheels, they never completely stop turning. So what I do is this. Don't look to see what the traffic is like on the cross street until you've come to a full stop. When you believe you've stopped, add a little more pressure to the brake. If you really stopped, nothing happens, but if your wheels are still turning, there will be a slight jerk. NOW check the highway for traffic.

@PatricHartmann: So if someone pulls out in front of you too close for you to stop, it's still your fault???

@Sean : Here in Switzerland, where I currently live, the answer is pretty much "yes" if it's a pedestrian, a bike or a motor bike (here with exceptions). If "someone" is another car, then the situation may vary. There are "standard situations" (e.g. a rear-end with no injuries and only minor damage) where there's no actual investigation and the perpetrator's insurance just pays. But when something major happens there is almost never a 100% fault on only one side. However, it seems not to be 25% anymore (or I got that wrong) according to the insurance guide here: https://www.svv.ch/de/ratgeber

@PatricHartmann: When I said "someone", I had in mind another car (probably because I'm from the States).

On commercial flights, key checklist items are forced by using a procedure call a "cross check". The one pilot must "challenge" another for those specific check list items. For non-cross checked items, pilots have discretion to implement checklists as they see fit.
Each pilot has their own practice. Some are sloppy and do nothing. Others fastidiously follow every item. Most commercial pilots tend to blow off most checklist items, especially anything outside the cockpit. For example, I fly American a lot and when the flight crew arrives I always watch to see if they do a walkaround and I have NEVER seen them do it. I complained about this to one of the top flight instructors at American and he said, "Well, they are supposed to do the walkaround." Yeah, they are SUPPOSED to, but do not do it.
It comes down to the personal discipline and attitudes of the pilot involved and how pressured they are to get the plane up in the air and on schedule.
On non-commercial flights and cargo flights often crews will become very lax. For example, in 2014 a Gulfstream crashed at Hanscom airfield killing everyone on board because they tried to takeoff with a gust lock engaged. This is impossible if you do even a minimal checklist because a control check is like the #1 or #2 thing on any checklist. A review of the tape showed that the crew in that case did ABSOLUTELY NOTHING verbal for cross checking. Furthermore, a review of the flight recorder for the aircraft showed that the crew had NEVER done a control check in 98% of the flights in that aircraft. Such laxity is not unusual in non-commercial flights.

What, specifically, do you mean when you say "blow off" a checklist.

@Terry I explained in my answer. Commercial pilots blow off checklist items, especially if they are time consuming or would involve walking around in the cold, like doing the walkaround. Multiple aircraft have crashed because the pilots did not check wing ice, and all they have to do was walk down the aisle and look out the window. Now that's lazy.

What I'm trying to find out is what you mean when you use the term "blow off". Perhaps that term now has a more explicit meaning than I'm aware of. For me, to "blow off" a check list could mean anything from rushing through it to not even running it. I'm just asking what you're intending to say. Are you saying that they often never do cockpit check lists? Are you saying they rush through the check lists verbally for the cockpit voice recorder? Are you saying they run the check lists at a normal speed but do not actually check the item?

@Terry Did you read my answer? I said they DO NOT DO THE ITEM. THEY DO NOT DO WALKAROUNDS. Go to any large airport and watch the PIC arrive and see if he does a walkaround. They DO NOT DO ICE CHECKS. As I already said, multiple aircraft have crashed because of wing ice or improper de-icing. This is only possible because the PIC NEVER VISUALLY CONFIRMED THE WING WAS CLEAR OF ICE as they are supposed to do on the check list.

I read your answer and then your replies to my comments in as an objective manner as I can.
Not seeing the PIC, in other words, the captain, do a walkaround is not a cause for concern. The Captain is not supposed to do the walkaround. In 15 years of flying 727s and 747s, I never did a walkaround.
Insofar as checking for ice from the cabin, it's from above the wing that you can see it. A walkaround will not enable you to see it other than that which is right at the leading edge.

@Terry According to the AA instructor I talked to, a walkaround is a company-required checklist item. The undercarriage and other critical items on the underside of the aircraft (fuel ports, flat tires) should be checked on ANY aircraft whether it is a 747 or C172. All Boeing manuals have detailed instructions on performing a pre-flight walkaround. I know ice is "above the wing". Did you even read my comment? I said you have to WALK DOWN THE AISLE to examine the wing and leading edge. How many pilots actually do this? Not many.

Let us continue this discussion in chat.

fastidiously follow every item nice reasoning you show there.

@TylerDurden an aisle wing inspection is only necessary to verify fluid holdover times after Type IV fluid application under specific circumstances.  If ice is noted at the gate but no precip is present then after the Type I fluid application it is icemans job to verify the wing is clean (and they are trained to do so via visual and tactile methods).  For walkarounds, a postflight and preflight walkaround may be combined into a single walkaround.  Walkarounds are generally done by the FO.  I've never departed without a completed walkaround.

This whole conversation is completely tangential to the point of the question and turned into a defensive "everybody-always-does-checklists-how-dare-you-say-otherwise" conversation which I don't see any point in having. The Gulfstream accident last year clearly shows a lot of professional pilots skip checklist items. So, my point is simple: the OP asks "How do pilots make sure they do every item." The answer is they don't always do every item. If they did, the Gulfstream accident (and many others) would never have happened.

@TylerDurden actually our argument is "we have 1000's of hours in commercial cockpits and have never witnessed gross checklist misuse" where yours is "there are a few accidents and my numerous anecdotes which mean no one uses checklists".  Sure, there are a few bad apples, but they are the rare exception, not the rule.


text:
Should landing light be off during line up and wait position?
What is the proper position for the landing lights when on the runway in a line up and wait position?

Counter-intuitively, the FAA answer (see chart on page 1-9 and text on page 1-10) is actually, they should be off during the line-up-and-wait phase.
When cleared to ...

“Line up and wait”—when entering the departure
  runway without takeoff clearance, turn on all exterior
  lights (except landing lights) to make your aircraft
  more conspicuous.

Then when takeoff clearance is received, the expectation is that landing lights will be turned on.
The best rationale I've seen for this is so that Tower controllers (and other aircraft) have an immediate visual cue that an aircraft "on the numbers" understands that it has been cleared for takeoff, or not.
Another FAA document, SAFO 11004 (these are "best practice" recommendations, not requirements):

Exterior Lighting:
o Taxi with taxi light on when moving, off when stopped.
o Turn on all exterior lights when crossing any runway.
o If cleared to “Line Up and Wait”, turn on all exterior lights except landing lights.
o When “Cleared for take-off”, turn on all exterior lights, including landing lights
o If you see an aircraft in take-off position on a runway with landing lights ON, that aircraft has
  most likely received its take-off clearance and will be departing immediately.

This is a good answer, except that I would note that the OP's question was "Should landing lights be off?" so I assume from the rest of your answer that you meant "yes, they should be off."

Excellent catch - fixed! Original answer was "no they should not be on," but given the question phrasing that needs to say "yes they should be off."  So much for the usual rule of "let your yes be yes, and let your no be no"!

Note that this is also the only time I'm aware of that the FAA wants you on a runway without every exterior light on the aircraft lit. If you're cleared to taxi across an active runway with "traffic holding in position" verifying the aircraft in position has their landing light off is a good safety check to distinguish between "They're sitting and waiting for me." versus "They misheard, think they're cleared for takeoff, and are going to hit me!"

i wouldn't count on the state of the landing light to mean anything in GA. people have lots of weird practices, like "i don't use the landing light except when its night time and the moon is less than half because it will burn out the bulb, which costs $147.34 to replace." For 121, the lights are standardized.

My understanding is that this is a recommendation and not a requirement.  I personally think that using lights to indicate intentions will only lead to further confusion.  If tower wants to know if someone understands a line up and wait call, it should be obvious if the lights are moving.  Otherwise, none of this applies during the day anyway because tower can't see the lights to begin with.

Another good reason for this is that sometimes there are taxiways to both sides of a runway and there may be an aircraft sitting directly across from you waiting to takeoff.  Please don't blind him!

I’d have it on for visibility. Since you’re on the runway and pointed forwards, no landing airplane will see it, and no airplane in the pattern will be really close. No airplane taking off will see it because they don’t have a rear view mirror.
It means one less thing to do before taking off, and lets you focus on the remaining checklist items before departing.
I’d turn it on once in position.

Landing lights signal clearance for takeoff. So aircraft on the ground who receive a clearance to cross in front of you may balk if they see you with landing lights on.

Based on Ralph J's answer quoting FAA docs, it appears that common sense isn't the appropriate procedure in this case.

If you intend to use your landing lights, there's no reason they should be off as your aircraft crosses the hold short position.  At a minimum it will serve to increase your visibility to other aircraft and service vehicles.  Taxi/ landing light courtesy does not apply to aircraft that are on an active runway.

Based on Ralph J's answer quoting FAA docs, it appears that common sense isn't the appropriate procedure in this case. Of course, military procedures may differ.

@FreeMan yeah, its SOP for us to turn them on crossing the hold short, which personally, I'd the only thing that makes sense.

Which is odd, since the military so often seems to avoid common sense!  ;)  (My son's in the Army, I've gained some experience.)

For aircraft which don't have taxi lights you will obviously have your (dual-purpose) landing light on when taking the runway, particularly at airports which don't have runway centerline lights & taxiway lead off lights to guide you.

Let's take this question from a position of logic- arguably you are in the most vulnerable position with traffic approaching from behind and your recommended to sit in the dark? That does not make a lot of sense to me. The landing light would not blind the inbound traffic, but rather cast a gentle light down the runway. I see two benefits from having the light on – The controller would advise the landing traffic that there is an aircraft on the active and waiting, why not make the visibility of said aircraft a little bit easier? Also as previous mentioned the taking off traffic that is one less thing to do. Do your lights camera action when taking the active runway including the landing light

Unfortunately, common sense seems to be contradicted by FAA regulations.


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What are some of the more common procedures when faced with a hung landing gear?
A hung landing gear is a potentially disastrous situation for a pilot flying a general aviation piston aircraft. During "shop talk" I've heard people say that the best thing to do is cycle the gear. During my multi-engine check ride I was told emphatically by my examiner that cycling a hung was the wrong thing to do.
What are some of the more common procedures suggested in POH/AFM documents for this situation? Can any deeper understanding be extracted from the common procedures?

You are asking for "opinions" which is not what this site is for. The better thing to ask is for what the aircraft manuals say.

Thank you for your feedback. I was aware I was asking the question improperly but I am curious about the topic. I think I can rework the question so it fits the guidelines.

What kind of airplanes are you interested in? Light pistons, jets, etc.? The answer varies from manufacturer to manufacturer, but even more so by certification requirements. I'd suggest narrowing the scope (possibly even to one airplane type or manufacturer, or about the certification requirements) in order to get the best answers.

I'll narrow the question further.

Not this: https://youtu.be/qP1XQzwRuV8

@JörgWMittag That's ridiculous. It also happened at the airport I operate out of right now.

As referenced in a comment, the generally accepted thing to do is to refer to the aircraft emergency checklist/AFM to see what it says to do.
This will vary by aircraft design, but usually involves testing the indicator lights, and then activating alternate means of extending the gear as needed.

First of all, you must determine if the gear is broken or the lights are broken.
Once you've determined that the lights are in working order, then you can trouble shoot the gear itself using the checklist in the plane.
If you've gone through the checklist in the plane, and you still don't have indication that the gear is down and locked, then there are many techniques that go beyond what's in the POH that rely on knowing how the gear works.
In some aircraft, the gear falls naturally using gravity, and is held down by a mechanical latch. If the gear fails to latch, then it is possible to slip the aircraft in the direction of the wheel that is not down. This will put the sideways slipstream on the gear, and could help to push it into the locked position.
If the nosewheel unfolds in the forward direction, it may be that slowing the plane to MCA can allow the nose gear to come forward and lock.
These are just a couple of examples, but knowing exactly how the gear works in your airplane will help you at a crucial time.

maybe add that pulling gs has sometimes convinced a gear to fully extend. Depends on the design, though.

I don't know what maneuver to perform in a normal category plane besides a slip to create any sidewards G forces

No, you increase the weight of the gear to overcome friction or whatever else prevents it from fully extending. Not only sideways, but normal gs can help in lowering the gear.

I think the AFM in the PA-28R actually gives maneuvers including slips and pulling Gs for a manual gear extension.

the only time I had a gear issue was in an Arrow, detailed here: http://aviation.stackexchange.com/questions/11536/who-should-handle-an-emergency-when-theres-both-a-certificated-pilot-and-a-cfi

@PeterKämpf ok, so you're suggesting, say a 3G pull-up. good idea.

@rbp I would suggest that the comment should he interpreted as you need to know the handling capability of your specific plane for the amount you need to perform. Simply stating an arbitrary number like 3G could lead to confusion about a specific airframes capability. Pulling negative G's could produce a fuel starvation effect and cause a larger problem than the stuck gear issue.

@RowanHawkins -- i wrote "normal category". that defines the "handling capability". you can educate yourself here: https://aviation.stackexchange.com/questions/12227/what-are-the-regulatory-categories-of-aircraft-defined-by-the-faa


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What are the regulations regarding plane spotting in the US?
I was told that certain plane spotting activities like taking photos of aircraft taking off and landing could be illegal in the US since 9/11? What are the regulations on this, and what should I be aware of before I set my camera up at the end of the runway?

Generally absent a specific prohibition you can take a photo of anything you can see with your eyes from public property (like a sidewalk). That includes airports, airplanes, bridges, tunnels, police officers, kittens, and unicorns.
(For more in-depth information check out Andrew Kantor's excellent article and Bert Krages' excellent one-page flyer on photographers' rights, or check out http://photography.stackexchange.com - they've covered airport photography, though not in any real depth, and I'm sure they have some street photographers well versed in the legal aspects of taking pictures.)

So what constitutes a "specific prohibition" on photography? Generally a clearly visible sign that says PHOTOGRAPHY PROHIBITED (the old Grumman facility in Bethpage had such signs on all of the fences where there was a decent view of the runway).
Absent such a clear prohibition you're free to take all the photos you want as long as you're on public property while you're doing it (i.e. "not trespassing on airport property"), but be aware that some law enforcement officials may not see it that way, and you may have to have some uncomfortable interactions with them.
In my experience most police officers are well versed in the law, though occasionally you'll find one who isn't. You're more likely to have trouble with a "rent-a-cop" security guard though.

If you want really good photographs (and you're not photographing at a major airport like JFK or O'Hare) you might want to speak to the airport management. At smaller airports someone - either airport personnel or a local pilot - might be able and willing to escort you airside where you can get some really great shots.
It helps in this situation if you have a body of work you can show (either published photos or art prints). The caveat is that many airports will also ask that you carry some kind of insurance while you're photographing on their property (and at larger airline fields that requirement can be substantial).

While this may be true, it is very common to have local airport people say that you are not allowed to take a photo which includes the tail number of any airplane on their ramp, and to have airport police that regularly run people off saying that they are not allowed to take pictures of the airplanes.  (I have a friend who is both a pilot and a professional photographer so he sees this a ton, at a lot of different airports!)

@Lnafziger yes, there are a lot of rentacops (and real ones too) who don't know the law. But that doesn't mean they can make up the law as they go along. Having some papers listing the relevant sections of laws helps, and always ask them (politely) to state which section of which law they're acting under and to see a supervisor in case they persist. Of course on airport property they have every right to kick you out for trespassing.

@Articuno if it's private property they can restrict whatever they want. Of course they can't restrict you photographing from public property (say a road) in the direction of the private property, which is why many such facilities have rather tall walls rather than fences, or fences with steel or other plates to prevent people seeing through them.

@Articuno Prior to the closing of the Grumman Bethpage facility Grumman's property included quite a bit of land. Persons photographing operations would be asked to leave Grumman property, which meant standing in the middle of the street, at which point you'd be run off for blocking traffic, or being far enough away that you weren't going to get any photographs worth taking. All that said, this is the Aviation stack exchange, and we're getting VERY far afield: The legality of posted "No Photography" signage is a more appropriate topic for [photo.se], I'd wager they've covered it already.

@Articuno a sign on private property that's visible from public property would have no effect on people who aren't on that private property. Of course rentacops are quite capable of ignoring such legal niceties and smashing your camera anyway.

This answer should specify which country it is about. Regulations about photogrphy in public spaces are different from nation to nation.

The ACLU notes that:

The Transportation Security Administration (TSA) acknowledges that photography is permitted in and around airline security checkpoints as long as you're not interfering with the screening process. The TSA does ask that its security monitors not be photographed, though it is not clear whether they have any legal basis for such a restriction when the monitors are plainly viewable by the traveling public.
The TSA also warns that local or airport regulations may impose restrictions that the TSA does not. It is difficult to determine if any localities or airport authorities actually have such rules. If you are told you cannot take photographs in an airport you should ask what the legal authority for that rule is.

Popular among photographers, The Photographer's Right, a summary of legal rights related to photography (prepared by a lawyer), says that:

There are some exceptions to the general rule. A significant one is that commanders of military installations can prohibit photographs of specific areas when they deem it necessary to protect national security.
Despite misconceptions to the contrary, the following subjects can almost always be photographed lawfully from public places:
accident and fire scenes, children, celebrities, bridges and other infrastructure, residential and commercial buildings, industrial facilities and public utilities, transportation facilities (e.g., airports), criminal activities, law enforcement officers

Some airports are more spotter-friendly than others. You can search online to find discussion forums on people's opinions which ones are better than others. Any airport that is private property (not many major ones, I believe) of course can do whatever they want, but many airports stop photography for a "safety" measure.
Standard IANAL disclosure.

mind that this applies to public property only. If the airport is privately owned the owners can set what restrictions they wish, and enforce them. But you'd expect at least a sign to warn you. And I've seen such signs at many airport checkpoints...

depends where you go in the world. remember the plight of the british spotters years ago when they were locked up in Greece .I admit it was military they were taking pics of,but I was warned at the perimeter fence at Athens airport for taking a pic of a antonov an24 that was parked by the fence.the police nearly arrested me.

@keithjackson the guys in Greece did far more than take pictures of aircraft from outside the airbase perimeter. They were arrested quite a distance INSIDE teh airbase perimeter, having knowingly intruded on a military facility. They were lucky they weren't shot, the guards on active bases have that authority.

license: Creative Commons - Attribution Share-Alike - https://creativecommons.org/licenses/by-sa/4.0/


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Reasons for significantly lower than normal approach
Not sure if this is going to be answerable to be honest, as I'm sort of asking for a bit of retroactive mind-reading! But here goes anyway!
I was driving along Clifton Drive North, Lytham Saint Annes, England on 17/11/18 (~3:30 pm if that matters) and I saw a plane approaching the adjacent Blackpool Airport at an exceptionally low altitude (not sure on model but looked like it might have been a Cessna 400-series). It's always hard to estimate altitude accurately (particularly given I was also driving at the time) but somewhere in the order of 200-300ft at the point it crossed over the road and descending (suffice it to say I was at least half expecting a crash!)
It was highly unusual - I've lived in the area for 5+ years, and travel that road frequently (typically at least 1-2 times a day and have been using the airport for even longer) and I've never seen a plane take that approach before. Here's the aerodrome chart for BPL:

Pretty much every plane I've ever been on (either flying or being flown) has approached and landed on runway 28 - even when coming from the west (e.g. coming from IOM) the approach has always been from the SW, bearing around 50° and then turning right to about 270-280° before descending to runway 28 to land.
As far as my limited knowledge allows I believe standard altitude for approach to BPL for this is 2000ft and there is not a cat in hell's chance that this plane was anywhere near that!
I think it is possible to land on runway 10 - but that the approach path for doing that is to be coming in from the east at 1600ft bearing 256-281° and flying over before turning right to 92° and descending. The OCA for this path is 450-1000 depending on aircraft category, it's distinctly possible that the plane was at 450 (as I mention above my altitude as estimate was based off Mk 1 eyeball from a moving car so unlikely to be especially accurate!) but curiously I'm 95% certain that the aircraft didn't pass over coming from the east, I had been on the road for a good few minutes and there's nothing that would have obscured my view of them doing so - and I must admit I'd been watching the sky quite closely as I'd spent a large amount of the drive musing that conditions were fantastic and wishing I'd booked myself a lesson for that afternoon!
The plot thickens in that probably less than a minute after the plane passed over a helicopter (reasonably large - probably a offshore-rig transport) flew over on roughly the same path, but if anything even lower!
So I was wondering whether there was some circumstance causing ATC to advise a different approach from typical and what that might be?
As I mention above conditions were fantastic wind was very slight (unusually so for Blackpool at this time of year!), visibility was great  - sunny with light hazy cloud that was well above (would probably have said 10,000-12,000ft +). Could operations at WRT (~6 NMi to the SSE) have had an influence?

The winds were coming from dead East 090°: See METAR, at >15kts. This strongly favours a landing on runway 10. The predominant winds in Blackpool are from the West, which may be why this is unusual to you.
The approach you mention is just one of the possibilities. The charts also give the option to approach directly from the West. Outside of the published approaches, one could imagine that ATC vectored the Cessna in on a quicker path to beat the incoming helicopter.

Thanks @Sanchises - that makes a lot of sense! Easterly winds are highly unusual here and I must admit I hadn't seen the chart showing the direct approach from the west before. The notion that they wanted to get the Cessna down before the heli is also blindingly obvious now that you mention it! I'll give it a few hours for form but I'd be surprised if any other answer can top this!

The low approach was likely due to the layout of the airfield, which has all the parking, pumps, on the north west corner of it. Also, once you're halfway down the runway there's no taxiways from the east half of the runway. 28/10 is 1870 meters (6135 feet) long and a light single probably needs 300-400 meters of it to stop. If the pilot landed 1/3 down the runway and then took 400 meters to stop they would have to backtrack to get back to the taxiway. If the pilot put it on the numbers then they might turn off on taxiway delta, or echo at the longest, clearing the runway sooner and having less taxi time.
Conversely, if you are in a light single on approach to 28 you'd want to aim for a 1/3 of the way, putting it down on the numbers means ages taxiing down the runway to the first turn-off point, all the while hearing the calls of those on late final having to go around because you're trundling down to Echo.

good point about the positioning of the taxiways - hadn't thought about that. The vast majority of aircraft I'll have seen on approach (and been on) will have been commercial and therefore presumably would have required more room to stop than a lighter GA so landing on 10 would have made it tight to make the turnoff points. Obviously with no more commercial traffic more of what I can expect to see will be the lighter craft.

I would agree with the previous posts that prevailing winds from the East is the likely solution, but you mentioned that this was significantly lower than most approaches.  One reason that one may fly a lower than normal approach is for a "no flap" landing.  I can't speak for a Cessna 400 series, but the flaps on high wing light Cessna aircraft are controlled electronically.  Should one lose their electrical system, they would land without flaps, at a higher rate of speed, and at a reduced angle of approach.  This is something that should be practiced from time to time.

No, the prevailing wind in pretty much the whole of the British Isles is from the west. The wind on that particular day was very unusual in that it was from the east.